• Title/Summary/Keyword: Mo electrode

Search Result 236, Processing Time 0.033 seconds

Metal Oxides Decorated Carbon Nanotube Freestanding Electrodes for High Performance of Lithium-sulfur Batteries (고성능 리튬-황 전지를 위한 금속산화물을 첨가한 탄소나노튜브 프리스탠딩 전극)

  • Yun Jung Shin;Hyeon Seo Jeong;Eun Mi Kim;Tae Yun Kim;Sang Mun Jeong
    • Korean Chemical Engineering Research
    • /
    • v.61 no.3
    • /
    • pp.426-438
    • /
    • 2023
  • Lithium-sulfur batteries, recently attracting attention as next-generation batteries, have high energy density but are limited in application due to sulfur's insulating properties, shuttle phenomenon, and volume expansion. This study used an economical and simple vacuum filtration method to prepare a freestanding electrode without a binder and collector. Carbon nanotubes (CNTs) are used to improve the electrical conductivity of sulfur, where CNT also acts as both collector and conductor. In addition, metal oxides (MOx, M=Ni, Mg), which are easy to adsorb lithium polysulfide, are added to the CNT/S electrode to suppress the shuttle reaction in lithium-sulfur batteries, which is a result of suppressing the loss of active sulfur material due to the excellent adsorption of lithium polysulfide by metal oxides. The MOx@CNT/S electrode exhibited higher capacity characteristics and cycle stability than the CNT/S electrode without metal oxides. Among the MOx@CNT/S electrodes, the NiO@CNT/S electrode displayed a high discharge capacity of 780 mAh g-1 at 1 C and an extreme capacity decrease to 134 mAh g-1 after 200 cycles. Although the MgO@CNT/S electrode exhibited a low discharge rate of 544 mAh g-1 in the initial cycle, it showed good cycle stability with 90% of capacity retention up to 200 cycles. Further, to achieve high capacity and cycle stability, the Ni0.7Mg0.3O@CNT/S electrode, mixed with Ni:Mg in the ratio of 0.7:0.3, manifested an initial discharge rate of 755 mAh g-1 (1 C) and a capacity retention rate of more than 90% after 200 cycles. Therefore, applying binary metal oxides to CNT/S provides a freestanding electrode for developing economical and high-performance Li-S batteries, effectively improving lithium polysulfide's high capacity characteristics and dissolution.

Study of contact resistance using the transmission line method (TLM) pattern for metal of electrode (Cr/Ag & Ni) (TLM pattern을 사용한 Cr/Ag 및 Ni 전극에 따른 접합 저항 연구)

  • Hwang, Min-Young;Koo, Ki-Mo;Koo, Sun-Woo;Oh, Gyu-Jin;Koo, Sang-Mo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2010.06a
    • /
    • pp.349-349
    • /
    • 2010
  • Great performance of many semiconductor devices requirs the use of low-resistance ohmic contact. Typically, transmission line method (TLM) patterns are used to measure the specific contact resistance between silicon and metal. In this works, we investigate contact resistance for metal dependent (Cr/Ag, Ni) using TLM pattern based on silicon-on-insulator (SOI) wafer. The electrode with Ni linearly increases contact resistance as the pattern distance increase from $15{\mu}m$ to $75{\mu}m$ in accumulation part, but non-linearly increase in inversion part. In additional, the electrode with Cr/Ag linearly increases contact resistance as the pattern distance increase from $15{\mu}m$ to $75{\mu}m$ in inversion part, but non-linearly increase in accumulation part.

  • PDF

Fabrication of All-Solution Processed Transparent Silver Nanowire Electrode Using a Direct Printing Process

  • Baek, Jang-Mi;Lee, Rin;Seong, Myeong-Mo
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2013.02a
    • /
    • pp.641-641
    • /
    • 2013
  • We report the transparentsilver nanowire electrode fabricated by a direct printing process, liquid-bridge-mediated nanotransfer molding. We fabricated silver nanowire arrays by liquidbridge- mediated nanotransfer molding using the silver nanoparticle ink and PEDOT:PSS polymer. Weinvestigated the formation of silver nanowire arrays by SEM and transmittance of the transparent silver nanowire electrode. We also measured the conductivity to confirm the potential of our approach.

  • PDF

The Effects of Partial Substitution of Mo and Heat Treatment on the Electrode Characteristics of ZrV0.1Mn0.7Ni1.2 Hydrogen Storage alloy (Ni-MH 2차 전지용 ZrV0.1Mn0.7Ni1.2 수소저장합금의 전극특성에 미치는 Mo의 부분치환과 열처리의 영향)

  • Han, Dongsoo;Oh, Myunghark;Jeong, Chigyu;Chung, Wonsub;Kim, Ingon
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.9 no.1
    • /
    • pp.16-24
    • /
    • 1998
  • Recently Zr-based $AB_2$ type hydrogen absorbing alloy has received much attention as a negative electrode material for the Ni-MH batteries because of its high capacity. In this study $ZrV_{0.1}Mn_{0.7}Ni_{1.2}$ alloy was chosen and the effects of heat treatment and a partial substitution of the Mo in Mn site on the various electrode properties were investigated. The alloys was prepared by arc melting (as-cast sample). Some of them were heat treated at $1,100^{\circ}C$ for 4 hours. After this they were differentiated by the different cooling rates of slow cooling and quenching. Various electrode characteristics such as activation process, high rate dischargeability and self discharge characteristic were investigated with the three types of electrodes. It was found that heat treated alloys resulted in an increase in plateau flatness of P-C isotherms however both discharge capacity and high rate capability were decreased. And the partial substitution of Mo for Mn in $ZrV_{0.1}Mn_{0.7}Ni_{1.2}$ alloy improved the self-discharge characteristic without the loss of discharge capacity (300mAh/g).

  • PDF

Magneto-transport properties of CVD grown MoS2 lateral spin valves

  • Jeon, Byeong-Seon;Lee, Sang-Seon;Hwang, Chan-Yong
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2016.02a
    • /
    • pp.336-336
    • /
    • 2016
  • We have investigated magneto-transport properties in a MoS2 lateral spin-valve structures for different ferromagnetic CoFe electrode shapes and MoS2 channel lengths. For these devices, high quality and large-scale MoS2 thin films were synthesized through sulfurization of epitaxial MoO3 films and these sulfurized-MoO3 thin films properties are in good agreements with measurements on exfoliated MoS2 film. Magneto-transport measurements show a clear rectangular magnetoresistance signal of 0.16% and a spin polarization of 0.00012%. By using the one-dimensional spin diffusion equation, we extracted the spin diffusion length and coefficient, finding them to be 12 nm and $1.44{\times}10-3cm2/s$, respectively. These small values of magnetoresistance and spin polarization could be enhanced by appeasement of conductivity mismatch between the ferromagnet and semiconductor interface.

  • PDF

Evaluations of Si based ternary anode materials by using RF/DC magnetron sputtering for lithium ion batteries

  • Hwang, Chang-Muk;Park, Jong-Wan
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2010.08a
    • /
    • pp.302-303
    • /
    • 2010
  • Generally, the high energy lithium ion batteries depend intimately on the high capacity of electrode materials. For anode materials, the capacity of commercial graphite is unlike to increase much further due to its lower theoretical capacity of 372 mAhg-1. To improve upon graphite-based negative electrode materials for Li-ion rechargeable batteries, alternative anode materials with higher capacity are needed. Therefore, some metal anodes with high theoretic capacity, such as Si, Sn, Ge, Al, and Sb have been studied extensively. This work focuses on ternary Si-M1-M2 composite system, where M1 is Ge that alloys with Li, which has good cyclability and high specific capacity and M2 is Mo that does not alloy with Li. The Si shows the highest gravimetric capacity (up to 4000mAhg-1 for Li21Si5). Although Si is the most promising of the next generation anodes, it undergoes a large volume change during lithium insertion and extraction. It results in pulverization of the Si and loss of electrical contact between the Si and the current collector during the lithiation and delithiation. Thus, its capacity fades rapidly during cycling. Si thin film is more resistant to fracture than bulk Si because the film is firmly attached to the substrate. Thus, Si film could achieve good cycleability as well as high capacity. To improve the cycle performance of Si, Suzuki et al. prepared two components active (Si)-active(Sn, like Ge) elements film by vacuum deposition, where Sn particles dispersed homogeneously in the Si matrix. This film showed excellent rate capability than pure Si thin film. In this work, second element, Ge shows also high capacity (about 2500mAhg-1 for Li21Ge5) and has good cyclability although it undergoes a large volume change likewise Si. But only Ge does not use the anode due to its costs. Therefore, the electrode should be consisted of moderately Ge contents. Third element, Mo is an element that does not alloys with Li such as Co, Cr, Fe, Mn, Ni, V, Zr. In our previous research work, we have fabricated Si-Mo (active-inactive elements) composite negative electrodes by using RF/DC magnetron sputtering method. The electrodes showed excellent cycle characteristics. The Mo-silicide (inert matrix) dispersed homogeneously in the Si matrix and prevents the active material from aggregating. However, the thicker film than $3\;{\mu}m$ with high Mo contents showed poor cycling performance, which was attributed to the internal stress related to thickness. In order to deal with the large volume expansion of Si anode, great efforts were paid on material design. One of the effective ways is to find suitably three-elements (Si-Ge-Mo) contents. In this study, the Si based composites of 45~65 Si at.% and 23~43 Ge at.%, and 12~32 Mo at.% are evaluated the electrochemical characteristics and cycle performances as an anode. Results from six different compositions of Si-Ge-Mo are presented compared to only the Si and Ge negative electrodes.

  • PDF

Electrical and Chemical Stability of Mo Gate Electrode for PMOS (PMOS에 적합한 Mo 전극의 전기적 화학적 안정성)

  • 노영진;이충근;홍신남
    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • v.41 no.4
    • /
    • pp.23-28
    • /
    • 2004
  • In this paper, the properties of Mo as PMOS gate electrodes were studied. The work-function of Mo extracted from C-V characteristic curves was appropriate for PMOS. To identify the electrical and chemical stability of Mo metal gate, the changes of work-function and EOT(Effective Oxide Thickness) values were investigated after 600, 700, 800 and 90$0^{\circ}C$ RTA(Rapid Thermal Annealing). Also it was found that Mo metal gate was stable up to 90$0^{\circ}C$ with underlying SiO$_2$through X-ray diffraction measurement. Sheet resistances of Mo metal gate obtained from 4-point probe were less than 10$\Omega$/$\square$ that was much lower than those of polysilicon.

Electrode properties upon the substitution of Mo for Mn in Zr-basd AB2-type Hydrogen Storage Alloys (Zr1-xTixV0.4Ni1.2Mn0.4-yMoy계 합금전극의 Mo 함량에 따른 물성 및 전극특성)

  • Seo, Chan-Yeol;Park, Choong-Nyeon
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.11 no.4
    • /
    • pp.189-202
    • /
    • 2000
  • $AB_2$ type Zr-based Laves phases alloys have been studied for potential application as a negative electrode in a Ni-MH battery. The $AB_2$-type electrodes have a much higher energy density than $AB_5$-type electrodes per weight, however they have some disadvantages such as poor activation behavior and cycle life etc. Nonetheless, the $AB_2$-type electrodes have been studied very extensively due to their high energy density. In this study, in order to develop the cycle life, the Mn of $AB_2$ alloy composition was substituted partially by Mo. The alloys were melted by arc furnace and remelted 4-5 times for homogeneity. The alloy powder was used below 200-325 mesh for experiments. The structures and phases of the alloys were analyzed by XRD, SEM and EDS, and measured the curve of a pressure-composition isotherms. The electrodes were prepared by cold pressing of the copper-coated(25 wt%) alloy powders, and tested by a half cell. The results are summarized as follows. The cycle life was improved with the increase of Mo amount in $Zr_{1-x}Ti_xV_{0.4}Ni_{1.2}Mn_{0.4}Mo_y$(x=0.3, 0.4) and the activation was faster, whereas the discharge capacity decreased.

  • PDF